Presumably from earlier *чацве́рг (*čacvjérh), ultimately from Proto-Slavic *četvьrtъkъ. The dropped -г (-h) in the nominative is retained in inflections of the word. Compare also Ukrainian четве́р (četvér) for this phenomenon, as well as дзе (dzje) and Ukrainian де (de) for word-initial h-dropping.
чацве́р • (čacvjér) m inan (genitive чацвярга́, nominative plural чацвяргі́, genitive plural чацвярго́ў)
| singular | plural | |
|---|---|---|
| nominative | чацве́р čacvjér |
чацвяргі́ čacvjarhí |
| genitive | чацвярга́ čacvjarhá |
чацвярго́ў čacvjarhóŭ |
| dative | чацвяргу́ čacvjarhú |
чацвярга́м čacvjarhám |
| accusative | чацве́р čacvjér |
чацвяргі́ čacvjarhí |
| instrumental | чацвярго́м čacvjarhóm |
чацвярга́мі čacvjarhámi |
| locative | чацвяргу́ čacvjarhú |
чацвярга́х čacvjarháx |
| count form | — | чацвяргі́1 čacvjarhí1 |
1Used with the numbers 2, 3, 4 and higher numbers after 20 ending in 2, 3, and 4.